By nature they won’t be able to edit SharePoint sites. FrontPage 2000 and 2002 don’t know how to open one.

Quite on the contrary. Older versions  of FrontPage CAN open and edit
WSS sites with disastrous results. This is a very real problem in my
mind, especially in corporate environments where multiple versions
of FrontPage could exist. We honestly haven't found a good technical
solution for this short of completely blocking FP editing  (we tried
an ISAPI filter for a while) but this also blocked network place
access to sites (another favorite backdoor trick our users utilize).

At a minimum, having a good business policy around this that is well
communicated is worth considering.

I know that this isn't a solution but I typically recommend no FrontPage
2003 (or obviously older versions) should be allowed in production. Only
in a test environment and then deploy changes to production. I hope I
can change my recommendation with Office 12 but that is yet to be seen.